This invention relates to an electronic analog timepiece and, in particular, to secondary timepiece functions produced in response to the predetermined settings or positions of the timepiece hands.
Timepieces that have analog displays include a crystal controlled oscillator and a stepping motor display driver. In order to provide for time correction, a correction control member such as a crown is positioned and rotated to produce movement of the hands of the timepiece in response to impulses provided by the stepping motor. U.S. Patents describing such electronic analog timepieces include U.S. Pat. No. 4,192,134 issued to Yoshida and U.S. Pat. No. 4,112,671 issued to Kato et al.
It is also known to use a single pushbutton switch for controlling various time setting modes for timepieces as illustrated in U.S. Pat. No. 3,953,964 issued to Suppa et al. and now recently allowed as a divisional reissue patent U.S. Pat. No. Re. 31,225. U.S. Pat. No. 4,192,134 issued to Yoshida shows a single pushbutton that achieves alternating forward and backward hand movement for time correction. A problem associated with analog stepping motor timepieces is that the timekeeping is disturbed if, for example, time zone changes are made during which the hour hand is repositioned. U.S. Pat. No. 4,357,693 issued to Plancon et al. shows a timepiece having a single manual pushbutton switch and providing proper compensation for the time used in making time correction in either direction.
Generally, timekeeping signals actuate drive circuits to provide drive pulses of selected wave shapes to drive a stepping motor which turns hour, minute and sometimes second hands. Timepieces which utilize stepping motors include U.S. Pat. No. 3,818,690 issued to Schwarzschild and U.S. Pat. No. 4,070,279 issued to Oudet et al.
Movement of the timepiece hands can occur at rapid rates in both the forward and reverse directions as disclosed in U.S. Pat. No. 4,173,863 issued to Motoki and U.S. Pat. No. 4,030,283 issued to Sauthier. Rapid movement of timepiece hands is also shown in U.S. Pat. No. 4,357,693 issued to Plancon et al. and having common assignee herewith.
Many alarm mechanisms have been used in prior art timepieces to set the alarm time. However, alarm setting mechanisms have not significantly improved in electronic quartz crystal timepieces. One attempt at improving alarm setting accuracy is disclosed in U.S. Pat. No. 4,223,523 issued to Kamijo. The electronic watch described in the patent includes an alarm which can be set by rotating the watch hands forward to the desired alarm time by slowly advancing the hands to the exact alarm setting. The timepiece then rapidly returns the hands to the actual present time. The watch of the Kamijo patent, however, sets the alarm time in the same manner in which it sets actual time and only by moving the hands in the forward or clockwise direction. In other words, an alarm time of 2 o'clock would be set by clockwise-positioning the minute hand in the direction of 12 o'clock and the hour hand in the direction of 2 o'clock. No provision appears to have been made for PM or AM alarm settings. Furthermore, to keep track of the alarm setting with respect to the actual time, counters have been implemented to count the number of drive pulses required to advance the hands to the alarm setting, to record the time elapsed in setting the alarm including the time required for advancement and return of the hands and to count the number of pulses required for hand return after the alarm time is set. These counters are required to compensate for the amount of time required to set the alarm time so that the alarm will be actuated at the proper moment.
U.S. Pat. No. 4,358,840 issued to Ono et al. discloses an electronic timepiece that detects electrically whether or not an alarm time is coincident with the present time without the use of mechanical means for detecting the location of the timepiece hands. A time difference counter is implemented for counting and storing the value corresponding to the difference in time between the alarm time and the present time. A display-time difference counter is implemented for calculating and storing the value corresponding to the difference in time between the display time and the present time. Another counter is implemented for receiving the content of the time difference counter when the content of the display-time difference counter is zero. As a result, the content of the other counter corresponds to the difference between the contents of the time difference counter and the display time difference counter. When the content of the other counter becomes zero, the alarm is activated. The timepiece operation requires relative (difference) relationships among alarm time, present time, and display time to be stored in memory locations and uses numerous counters, switches, and discriminators to control the drive of the time-indicating hands based on these stored differences.
What is needed is an electronic analog timepiece which provides simplified accurate electronic setting of the alarm time using timepiece hands of the analog display for setting the alarm.
Accordingly, an object of the invention is to provide for simplified electronic setting of alarm time using minute and second hands of the display to set the hour and minutes of the alarm time.
Another object of the invention is to provide for alarm time setting by rotating timepiece hands in either the clockwise or counterclockwise directions.
Another object of the invention is to set alarm time and display either alarm time or actual, updated real time without having to take into account the amount of time elapsed in either setting alarm time or when selectively displaying either alarm time or real time.
Yet a further object of the invention is to set the alarm time hour by rotating the timepiece minute hand over a span of minutes from the twelve o'clock position, and to obtain the same alarm time hour setting by moving the timepiece minute hand to any discrete position within a range of minutes having a low limit equal to a whole number multiple of five, i.e., 10, and a high limit equal to the same whole number multiple of five plus four, i.e. 14.
Another object of the invention is to provide fast rotation of the timepiece hands as they move from the display of one time setting to another, i.e. from alarm time setting to real or actual time setting.
Another object of the invention is to provide for actual time to be continuously updated without interruption regardless of the time setting operation being performed.